1. Technical Field
The present invention relates to an elastic member for an ink jet recording apparatus and an ink jet recording apparatus including the elastic member, and an elastic member for an ink tank and an ink tank including the elastic member.
2. Related Art
An ink jet recording apparatus of the related art is constituted in such a manner that an ink jet recording head which ejects ink droplets corresponding to printing signals is mounted on a carriage which reciprocates in a paper width direction of recording paper and that ink is supplied from an external ink tank to the recording head. Such an ink storage container such as the ink tank is constituted in such a manner that it can be detachably mounted on the carriage, taking convenience in handling into consideration in a small-sized recording apparatus.
Such an ink storage container of the related art is constituted in such a manner that a porous material is contained and impregnated with the ink to retain the ink by capillary force, in order to prevent leakage of the ink from the recording head. On the other hand, with the requirement of improving print quality and print speed, the number of nozzle openings of the recording head increases, resulting in a tendency to increase ink consumption per unit of time.
In order to comply with such a tendency, desirably, it is necessary to increase the amount of ink contained in the ink storage container, and in order to increase the amount of ink, it is necessary to increase the volume of the porous material. However, in order to retain the ink by capillary force, the volume must be increased by increasing the base area, because the height, namely the water head, is limited. This causes a problem of increasing the size of the carriage to result in an increase in the size of the recording apparatus.
Of course, it is also conceivable that retention force of the ink is increased by using a porous material having a small average pore size. However, fluid resistance to a flow of the ink increases, so that not only it becomes difficult to stably supply the ink corresponding to ink consumption in the recording head, but also it becomes difficult to surely supply the ink from a region depart from an ink supply port to the recording head. As a result, there is encountered a new problem that the ink in the ink storage container is not used up to cause waste.
In order to solve such problems, JP-A-2003-94682 discloses an ink cartridge for a ink jet recording apparatus of the related art, which comprises a container provided with a lower ink storage chamber, an upper ink storage chamber, an ink supply port for supplying ink to a recording head, an ink suction flow passage connecting the lower ink storage chamber and the upper ink storage chamber, an ink flow passage connecting the ink supply port and the upper ink storage chamber and an air communication portion for communicating the lower ink storage chamber to the air, and a negative pressure generating mechanism contained in the container and disposed in the course of the ink flow passage. According to this ink cartridge of the related art, the ink is supplied to the recording head through the negative pressure generating mechanism, so that pressure fluctuation caused by changes in the amount of ink can be prevented as much as possible. A membrane valve used in the negative pressure generating mechanism has been demanded to improve adhesion of a differential pressure valve storage chamber in which the membrane valve is contained and a membrane valve holding plate to the membrane valve, in order to prevent response variations of the negative pressure generating mechanism to decrease variations in ink supply capacity.
Further, when the ink cartridge is mounted on the carriage, the ink supply port of the ink cartridge is provided with a seal member, and an ink supply needle communicated with the recording head is inserted into a hole of this seal member. Higher adhesion has been demanded between the ink supply needle and the seal member so that no ink leaks from between the ink supply port and the seal member. Furthermore, this seal member has been demanded to have higher core adjustability (to maintain a sealed state even when misalignment occurs between the ink supply needle and the seal member).